IPC-TM-650 EN 2022 试验方法--.pdf - 第663页

5.8.3 Cl ass T Evaluation 5.8.3.1 Three separa te se ts of m easurem ents are to be recorded for the uncoated specimen, the ‘as received’ speci- men, and the specimen afte r solder exposure. Each set of readings shall be…

b. Maintain temperature at 65 ± 2 °C [149 ± 3.6 °F] for 3,

+0.5/-0 hours

c. Lower the temperature from 65 ± 2 °C [149 ± 3.6 °F] to

25 ± 2 °C [77 ± 3.6 °F] over a time span of 2.5 hours ± 5

minutes

There shall be no delay between cycles.

5.7.2 Class H Measurement

5.7.2.1

Disconnect the 50 VDC bias voltage source before

taking the insulation resistance measurements. Electrical con-

nections to specimens shall be made such that the bias and

test voltages are of the same polarity. Insulation resistance

shall be read as specified in 5.7.1.4. Apply 100 VDC on the

specimens test points with the resistance meter and take the

reading after one minute with the patterns under test condi-

tions.

5.7.2.2

For qualification testing, measure and record resis-

tance once every 24 hours (if insulation resistance quality

measurements are required, see 5.7.3.1), between the 2nd

and 3rd hour of the high termperature phase of each cycle.

These measurements are to be conducted without opening

the chamber. After completion of the temperature cycling, dis-

connect the bias voltage, remove the specimens from the

chamber, and measure and record insulation resistance after

the specimen has been at ambient conditions for more than

one hour but less than two hours.

5.7.2.3

For conformance testing using pattern C, the mea-

surements should be taken after disconnectng the bias volt-

age, removing the specimens from the test chamber and

allowing the specimens to stabilize to laboratory ambient con-

ditions for one hour and not exceeding two hours. See 6.2.

5.7.3 Class H Evaluation

5.7.3.1

Each test specimen shall be evaluated for insulation

resistance quality following and/or during the stated condi-

tions. Although several insulation resistance readings may be

taken during the test, only the final (18th cycle) readings in

high temperature phase in the chamber and the reading taken

outside the chamber shall be used to determine pass/fail cri-

teria.

5.7.3.2

After completion of all electrical testing, the test

specimens shall be examined for blisters or delamination fol-

lowing the 24-hour stabilization at ambient laboratory condi-

tions. See 6.2.

5.8 Class T Procedures

5.8.1 Class T Testing

5.8.1.1

Condition the specimens at 50 ± 2 °C [122 ± 3.6 °F]

with no added humidity, for a period of 24 hours.

5.8.1.2

Remove the specimens from the oven and cool to

laboratory ambient temperature. Apply 100 VDC to comb pat-

terns E and F of each test specimen. See 6.2.

5.8.1.3

The test points for qualification are at each pair of

terminals (finger tabs) on the E and F comb patterns. One of

the test points is connected to the negative terminal and the

other to the positive terminal. For quality conformance, the

pair of test points is 1 to 2 on the C pattern. One side of the

C pattern should be connected to the negative terminal and

the other side to the positive.

5.8.1.4

Place the specimens in the test chamber in the ver-

tical position and under a condensation drip shield.

Each chamber load shall contain at least one

uncoated board that is representative of the cleaning process

used prior to solder mask application for each solder mask

tested.

5.8.1.5

Close the chamber door and bring the chamber to

65 ± 2 °C [149 ± 3.6 °F] and 90% relative humidity.

5.8.1.6

Allow specimens to stabilize at test conditions for 24

hours.

5.8.2 Class T Measurement

5.8.2.1

Connect the resistance meter to the appropriate test

points. For qualification testing, one of the test points of the

two terminal E and F patterns are connected to the negative

terminal and the other test point to the positive. For quality

conformance testing, one side of the C pattern (‘‘Y’’ pattern)

should be connected to the negative terminal and the other

side to the positive.

5.8.2.2

Apply 100 VDC on the specimens test points with

the resistance meter and take the reading after one minute

with the patterns under test conditions.

Number

2.6.3.1

Subject

Solder Mask - Moisture and Insulation Resistance

Date

03/07

Revision

IPC-TM-650

—

Note:

NOTE:

Other

readings

are

optional

and

may

used

for

diagnostic

information

aborting

the

test.

Page

5.8.3 Class T Evaluation

5.8.3.1

Three separate sets of measurements are to be

recorded for the uncoated specimen, the ‘as received’ speci-

men, and the specimen after solder exposure. Each set of

readings shall be averaged and shall be greater than the mini-

mum listed in the relevant specification. No individual insula-

tion resistance (IR) value may be less than 0.1 x IR

min

, where

min

is the minimum in the set of IR values measured. Two

measurements may be excluded from calculating the average

if there is an assignable cause of low insulation resistance that

can be attributable to the laminate itself or to the process

used to produce the board. Such assignable causes include

but are not limited to:

a. Contamination of the insulating surface of the board such

as lint, solder splines, or water droplets from the condition-

ing chamber.

b. Incompletely etched patterns that decrease the insulating

space between conductors by more than the amount

allowed in the appropriate design requirements drawing.

c. Scratched, cracked or obviously damaged insulation

between conductors.

5.8.3.2

The average insulation resistance (IRavg) is calcu-

lated from:

avg

= 10

[

log IR

]

Where:

N = Number of test points (12 nominal)

= Individual insulation resistance measurements.

5.8.3.3

After completion of all electrical testing and following

the nominal 24-hour stabilization at laboratory ambient tem-

peratures (see 5.8.1.6), the test specimens shall be examined

for mealing, blisters, delamination or other forms of degrada-

tion.

6 Notes

6.1

Initial wire placement must be maintained to ensure

reproducible results.

6.2

Specimens may be stabilized at ambient conditions

specified, inside the chamber.

Number

2.6.3.1

Subject

Solder Mask - Moisture and Insulation Resistance

Date

03/07

Revision

IPC-TM-650

Page

1 Scope

This test method defines the procedures for deter-

mining the surface insulation resistance of a copper foil clad

flexible dielectric material in the presence of moisture. This

test method may be used for testing both metal clad dielec-

tric as produced per IPC-4204 and bondply dielectric that

must be evaluated for surface insulation resistance in a lami-

nated format as metal clad dielectric.

The moisture resistance test is performed for the purpose of

evaluating, in an accelerated manner, the resistance of mate-

rials to the deleterious effects of high humidity and heat con-

ditions. The test method is designed to simultaneously assess

leakage current caused by ionized water films and electro-

chemical degradation (corrosion and dendritic growth) of the

test vehicle.

2 Applicable Documents

2.1 IPC

Acceptability Guidelines

3 Test Specimen

The test specimen consist of an

etched conductor pattern in accordance with Figure 1. Test a

minimum of three test specimens per clad side. For double

clad material, a separate sample unit

be prepared for

each side.

3.1

The test points for comb patterns are 1 to 2, 2 to 3, 3 to

4, and 4 to 5. Test points 1-3-5 are connected to the positive

(+) terminal, and test points 2-4 are connected to the negative

(-) terminals of the resistance meter.

4 Apparatus

4.1 Test Chamber

A test chamber capable of producing

and recording an environment of 65 °C ± 2 °C [149 °F ±

3.6 °F] and 85% - 93% relative humidity and which will allow

the insulation resistance to be measured while the specimens

are under the specified conditions. This chamber is to be used

for static insulation resistance testing, involving a single tem-

perature and relative humidity to stress the test specimen over

the specified test time.

4.2 Power Supply

A power supply capable of producing a

bias potential of 100 volts dc with a tolerance of ± 10%.

4.3 Resistance Meter

A resistance meter capable of read-

ing 10

ohms or greater, with a measurement error not to

exceed 10%, with a test voltage of 500 volts dc.

4.4 Other Equipment or Materials

4.4.1

Soft bristle brush.

4.4.2

Deionized or distilled water (2 megohm cm minimum

resistivity recommended).

4.4.3

Isopropyl alcohol.

4.4.4

Single-stranded* PTFE or other fluorocarbon insulated

wire. (Shielded wire recommended.) [*single-stranded mini-

mizes flux wicking]

4.4.5

Soldering iron (25 - 40 watts).

4.4.6

Drying oven capable of maintaining at least 60 °C.

IPC-2632-1

▼

3000 Lakeside Drive, Suite 105N

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.6.3.2

Subject

Surface Insulation and Moisture Resistance,

Copper Clad Flexible Dielectric Material

Date

8/14/15

Revision

Originating Task Group

D-15

Association

Connecting

Electronics

Industries

6.0mm

—

LAND

AREAS

0.050"]

6.0mm

all

0.64mm

[0.025"]

wide,

between

lines

1.27mm

50.8mm

The

lines

are

The

spacing

IPC-A-600

shall

Figure

Insulation

resistance

test

pattern

Material

this

Test

Methods

Manual

was

voluntarily

established

Technical

Committees

PC.

This

material

advisory

only

and

use

adaptation

，

entirely

voluntary.

IPC

disclaims

all

liability

any

kind

the

use,

application,

adaptation

this

material.

Users

are

also

wholly

responsible

for

protecting

themselves

against

all

claims

liabilities

for

patent

infringement.

Equipment

referenced

for

the

convenience

the

user

and

does

not

imply

endorsement

IPC.

Page

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